Haseeb-Qureshi

Inside the Claude Code source

Anthropic's Claude Code CLI source code leaked onto GitHub recently. All of it. About 1,900 files and a lot of TypeScript.

I read through the key modules. What follows is a breakdown of the surprising parts: how the system actually works, where Anthropic made clever engineering choices, and where their approach diverges from OpenAI's Codex in ways you wouldn't guess from using either tool.

Lifecycle of a request

Here's what happens when you type a message into Claude Code:

sindresorhus

Pure ESM package

The package that linked you here is now pure ESM. It cannot be require()'d from CommonJS.

This means you have the following choices:

1. Use ESM yourself. (preferred)
   Use import foo from 'foo' instead of const foo = require('foo') to import the package. You also need to put "type": "module" in your package.json and more. Follow the below guide.
2. If the package is used in an async context, you could use await import(…) from CommonJS instead of require(…).
3. Stay on the existing version of the package until you can move to ESM.

ThinhPhan

.PHONY: install uninstall test set-default

test:
	sudo apt install plymouth-x11
	sudo plymouthd ; sudo plymouth --show-splash ; for ((I=0; I<10; I++)); do sleep 1 ; sudo plymouth --update=test$I ; done ; sudo plymouth --quit

uninstall:
	rm -rv /usr/share/plymouth/themes/first || true

install: uninstall